Lanier's 8-inch rise useless

Drought keeps lake 19 1/2 feet below summer level

January 27, 2008
By Stacy Shelton, The Atlanta Journal-Constitution

Atlanta -- Three months ago, state and federal water experts warned that Lake Lanier could fall to a depth never intended for the man-made reservoir, jeopardizing metro Atlanta water supplies.

It didn't. But in mid-November, Lanier did surpass its 26-year-old record low and then continued falling through December. The lake's been on a minirebound since, rising about 8 inches.

That's nothing to get excited about, especially since climate forecasters expect the historic drought to keep a chokehold on metro Atlanta through at least April, the longest outlook provided.

This year has already started out worse than last. According to the U.S. Geological Survey, less than half the normal amount of rain has fallen on Lanier in January, and northwest Georgia streams continue their months-long trend of setting daily records for low flows.

"We're by no means anywhere close to being out of the situation," said Mark Crisp, a water expert in Atlanta with the national consulting firm C.H. Guernsey & Co. "Lanier, quite frankly, hasn't refilled at all, and the forecast is for it to continue to go down."

That could mean going into the summer in a "very precarious position," Crisp continued. "Never have we gone into the summer with Lanier [this low]. That's horrible. How that reservoir is going to respond during the summer, no one knows because we've never been here before."

Crisp is betting Lanier will not rise to more than 11 feet below its full summer level. Currently, the lake is 19.5 feet below, evidenced by dry swimming holes and landlocked docks.

If metro Atlanta averts a Katrina-size disaster of running out of water, it will probably be due to the same factors that helped the region avoid it so far.

Experts say the difference has been rain, conservation and dam management.

Aris Georgakakos, director of the Georgia Water Resources Institute at Georgia Tech, said of the three factors, the greatest impact has been the U.S. Army Corps of Engineers' decision to throttle back on the water flowing out of Lanier.

Today the corps is releasing about one-third the amount of water from Lanier that it did in November. The main reason is the lower half of the basin, including the Flint River, has gotten a lot more rain than Lanier. That means the corps hasn't had to release Lanier's water to make up for deficits downstream.

What that means in real numbers is that 16 billion gallons of water a day is flowing into the Apalachicola River at the bottom of the Chattahoochee, after months of receiving an anemic 3.2 billion gallons a day.

"We need to be very careful of how much water we release from Lake Lanier," Georgakakos said. "Imagine what would happen if somehow none of this works [and both releases and water use increase] and we don't get enough rain in the spring. Lanier depletes."

Metro Atlanta's water-saving efforts are also helping, Georgakakos said. Every time someone takes a shorter shower or flushes less often, it's that much less water needed from Lanier and the Chattahoochee.

The only water the corps is currently releasing from Lanier is for this region's water needs — for supply and to leave enough water in the river to handle the daily discharges of treated sewage.

Georgakakos estimates the difference for Lanier could add up to two to four feet over about nine months.

Georgia Environmental Protection Division Director Carol Couch agrees that conservation matters. At the end of November, she imposed a total ban on most outdoor water use in North Georgia and is enforcing Gov. Sonny Perdue's mandate to reduce water use by 10 percent over last winter.

While Lanier continues its disappearing act, other lakes are returning to normal. Most notable is Allatoona Lake, the water source for about 800,000 people. It reached its normal winter level earlier this month. Other, smaller reservoirs, including ones in Douglas and Clarke counties, also have refilled.

Crisp, the consultant, said the difference is Lanier's huge size, at 38,000 acres, and relatively small drainage basin. Lanier is near the top of its two feeder streams, at a juncture where both — including the Chattahoochee — are still skinny. That means filling up Lanier is the equivalent of using a straw to fill up a bathtub.

Allatoona, on the other hand, is about a third the size of Lanier with about the same size drainage area.

The same is true for the smaller reservoirs. It's easier to fill them up, but also easier to drain them.

Another big difference has been rain. The Allatoona basin, located northwest of Atlanta, has received more than Lanier.

State Climatologist David Stooksbury with the University of Georgia said despite the dire predictions of three months ago, the chance of metro Atlanta running out of water in the winter is negligible. This is when the region gets a lot of rain, and because of the cooler temperatures, evaporation is low.

"The concern was never the winter," Stooksbury said. "The real concern is June through October this year. If we do not receive enough rainfall, we just won't have that cushion that we need to get us through the summer."

That means thinking about the worst-case scenario again. This time, communities are better prepared. Those that pull from the lakes have prepared to pull from lower levels. Others that have vulnerable water sources have connected to neighbors that have more stable supplies.

Even if Lanier drops below the bottom of its conservation pool, it still has 282.7 billion gallons of water. At that level, the corps would have to shut off its hydropower turbines but could still force through plenty of water to meet metro Atlanta's needs downstream, where DeKalb, Cobb and Fulton counties and the city of Atlanta withdraw their water from the Chattahoochee.

Corps officials say they can maintain those flows, even if the lake were to drop an additional 35 feet below the bottom of the conservation pool — or about 50 feet below where it is today.

Georgakakos, Georgia Tech's water expert, said big droughts like this one tend to last four to five years.

"We may have another two years to go," Georgakakos said.